[lld] [llvm] [LTO] Override TargetABI from module flags if present when creating TargetMachine (PR #126497)
Kito Cheng via llvm-commits
llvm-commits at lists.llvm.org
Thu Mar 6 19:11:23 PST 2025
https://github.com/kito-cheng updated https://github.com/llvm/llvm-project/pull/126497
>From cca7238486736793248ca898e171633efc5bbaad Mon Sep 17 00:00:00 2001
From: Kito Cheng <kito.cheng at sifive.com>
Date: Mon, 10 Feb 2025 00:57:03 -0800
Subject: [PATCH 1/5] [LTO] Override TargetABI from module flags if present
when creating TargetMachine
RISC-V's data layout is also determined by the ABI, not only the target triple,
however the TargetMachine is created with the target triple's data layout,
that is not always correct. This patch changes the TargetMachine's data
layout to the one specified in the module flags if present.
The same problem will happen with other targets like MIPS, but unfortunately,
MIPS didn't emit the target-abi into the module flags, so this patch only
fixes the issue for RISC-V.
NOTE: MIPS with -mabi=n32 can trigger the same issue.
Another possible solution is add new parameter to the TargetMachine
constructor, but that would require changes in all the targets.
---
lld/test/ELF/lto/riscv-ilp32e.ll | 25 +++++++++++++++++++++++++
llvm/lib/LTO/LTOBackend.cpp | 12 +++++++++++-
2 files changed, 36 insertions(+), 1 deletion(-)
create mode 100644 lld/test/ELF/lto/riscv-ilp32e.ll
diff --git a/lld/test/ELF/lto/riscv-ilp32e.ll b/lld/test/ELF/lto/riscv-ilp32e.ll
new file mode 100644
index 0000000000000..ea2b57d483358
--- /dev/null
+++ b/lld/test/ELF/lto/riscv-ilp32e.ll
@@ -0,0 +1,25 @@
+; REQUIRES: riscv
+;
+; Check that we don't crash on DataLayout incompatibility issue.
+;
+; RUN: llvm-as %s -o %t.o
+; RUN: ld.lld %t.o -o %t.elf
+; RUN: llvm-readobj -h %t.elf | FileCheck %s --check-prefixes=CHECK
+;
+; CHECK: Machine: EM_RISCV (0xF3)
+; CHECK: EF_RISCV_RVE (0x8)
+
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32-S32"
+target triple = "riscv32-unknown-unknown-elf"
+
+define dso_local i32 @_start() #0 {
+entry:
+ ret i32 0
+}
+
+attributes #0 = { "target-cpu"="generic-rv32" "target-features"="+32bit,+e" }
+
+!llvm.module.flags = !{!0}
+
+!0 = !{i32 1, !"target-abi", !"ilp32e"}
diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp
index 8a2dddce4892c..b9d2242d4a2cf 100644
--- a/llvm/lib/LTO/LTOBackend.cpp
+++ b/llvm/lib/LTO/LTOBackend.cpp
@@ -221,8 +221,18 @@ createTargetMachine(const Config &Conf, const Target *TheTarget, Module &M) {
else
CodeModel = M.getCodeModel();
+ TargetOptions TargetOpts = Conf.Options;
+
+ if (TargetOpts.MCOptions.ABIName.empty()) {
+ Metadata *ABI = M.getModuleFlag("target-abi");
+ if (ABI) {
+ const StringRef &ModABI = cast<MDString>(ABI)->getString();
+ TargetOpts.MCOptions.ABIName = ModABI;
+ }
+ }
+
std::unique_ptr<TargetMachine> TM(TheTarget->createTargetMachine(
- TheTriple, Conf.CPU, Features.getString(), Conf.Options, RelocModel,
+ TheTriple, Conf.CPU, Features.getString(), TargetOpts, RelocModel,
CodeModel, Conf.CGOptLevel));
assert(TM && "Failed to create target machine");
>From d9972a8ae24c7909215f7c93f8c41ddec4837ccc Mon Sep 17 00:00:00 2001
From: Kito Cheng <kito.cheng at sifive.com>
Date: Wed, 12 Feb 2025 00:47:55 -0800
Subject: [PATCH 2/5] address comment
---
llvm/test/LTO/RISCV/lit.local.cfg | 2 ++
{lld/test/ELF/lto => llvm/test/LTO/RISCV}/riscv-ilp32e.ll | 6 ++----
2 files changed, 4 insertions(+), 4 deletions(-)
create mode 100644 llvm/test/LTO/RISCV/lit.local.cfg
rename {lld/test/ELF/lto => llvm/test/LTO/RISCV}/riscv-ilp32e.ll (79%)
diff --git a/llvm/test/LTO/RISCV/lit.local.cfg b/llvm/test/LTO/RISCV/lit.local.cfg
new file mode 100644
index 0000000000000..17351748513d9
--- /dev/null
+++ b/llvm/test/LTO/RISCV/lit.local.cfg
@@ -0,0 +1,2 @@
+if not "RISCV" in config.root.targets:
+ config.unsupported = True
diff --git a/lld/test/ELF/lto/riscv-ilp32e.ll b/llvm/test/LTO/RISCV/riscv-ilp32e.ll
similarity index 79%
rename from lld/test/ELF/lto/riscv-ilp32e.ll
rename to llvm/test/LTO/RISCV/riscv-ilp32e.ll
index ea2b57d483358..45cc1b78f649a 100644
--- a/lld/test/ELF/lto/riscv-ilp32e.ll
+++ b/llvm/test/LTO/RISCV/riscv-ilp32e.ll
@@ -1,10 +1,8 @@
-; REQUIRES: riscv
-;
; Check that we don't crash on DataLayout incompatibility issue.
;
; RUN: llvm-as %s -o %t.o
-; RUN: ld.lld %t.o -o %t.elf
-; RUN: llvm-readobj -h %t.elf | FileCheck %s --check-prefixes=CHECK
+; RUN: llvm-lto2 run -r %t.o,_start %t.o -o %t.elf
+; RUN: llvm-readobj -h %t.elf.0 | FileCheck %s --check-prefixes=CHECK
;
; CHECK: Machine: EM_RISCV (0xF3)
; CHECK: EF_RISCV_RVE (0x8)
>From b444ee2d3c76e93e03eb30408a044f8f31f62968 Mon Sep 17 00:00:00 2001
From: Kito Cheng <kito.cheng at sifive.com>
Date: Mon, 3 Mar 2025 22:48:35 +0800
Subject: [PATCH 3/5] Add Module::getTargetABIFromMD
---
llvm/include/llvm/IR/Module.h | 3 +++
llvm/lib/IR/Module.cpp | 8 ++++++++
llvm/lib/LTO/LTOBackend.cpp | 5 ++---
3 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/llvm/include/llvm/IR/Module.h b/llvm/include/llvm/IR/Module.h
index 12b50fc506516..3368184af4103 100644
--- a/llvm/include/llvm/IR/Module.h
+++ b/llvm/include/llvm/IR/Module.h
@@ -1065,6 +1065,9 @@ class LLVM_ABI Module {
/// Set the target variant version build SDK version metadata.
void setDarwinTargetVariantSDKVersion(VersionTuple Version);
+
+ /// Returns target-abi from MDString, null if target-abi is absent.
+ StringRef getTargetABIFromMD();
};
/// Given "llvm.used" or "llvm.compiler.used" as a global name, collect the
diff --git a/llvm/lib/IR/Module.cpp b/llvm/lib/IR/Module.cpp
index c7b9f8744d8d3..3ee53528a825e 100644
--- a/llvm/lib/IR/Module.cpp
+++ b/llvm/lib/IR/Module.cpp
@@ -915,3 +915,11 @@ VersionTuple Module::getDarwinTargetVariantSDKVersion() const {
void Module::setDarwinTargetVariantSDKVersion(VersionTuple Version) {
addSDKVersionMD(Version, *this, "darwin.target_variant.SDK Version");
}
+
+StringRef Module::getTargetABIFromMD() {
+ StringRef TargetABI = "";
+ if (auto *TargetABIMD =
+ dyn_cast_or_null<MDString>(getModuleFlag("target-abi")))
+ TargetABI = TargetABIMD->getString();
+ return TargetABI;
+}
diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp
index b9d2242d4a2cf..6c8708e7591ec 100644
--- a/llvm/lib/LTO/LTOBackend.cpp
+++ b/llvm/lib/LTO/LTOBackend.cpp
@@ -224,9 +224,8 @@ createTargetMachine(const Config &Conf, const Target *TheTarget, Module &M) {
TargetOptions TargetOpts = Conf.Options;
if (TargetOpts.MCOptions.ABIName.empty()) {
- Metadata *ABI = M.getModuleFlag("target-abi");
- if (ABI) {
- const StringRef &ModABI = cast<MDString>(ABI)->getString();
+ StringRef ModABI = M.getTargetABIFromMD();
+ if (!ABI.empty()) {
TargetOpts.MCOptions.ABIName = ModABI;
}
}
>From 92771eb2e31be1dc969a61427f7d35746d3bf3b5 Mon Sep 17 00:00:00 2001
From: Kito Cheng <kito.cheng at sifive.com>
Date: Mon, 3 Mar 2025 22:56:00 +0800
Subject: [PATCH 4/5] fix build fail
---
llvm/lib/LTO/LTOBackend.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp
index 6c8708e7591ec..08955387ecfc3 100644
--- a/llvm/lib/LTO/LTOBackend.cpp
+++ b/llvm/lib/LTO/LTOBackend.cpp
@@ -225,7 +225,7 @@ createTargetMachine(const Config &Conf, const Target *TheTarget, Module &M) {
if (TargetOpts.MCOptions.ABIName.empty()) {
StringRef ModABI = M.getTargetABIFromMD();
- if (!ABI.empty()) {
+ if (!ModABI.empty()) {
TargetOpts.MCOptions.ABIName = ModABI;
}
}
>From d747098207b45126cc670d089280ecf9acdc217f Mon Sep 17 00:00:00 2001
From: Kito Cheng <kito.cheng at gmail.com>
Date: Fri, 7 Mar 2025 11:11:14 +0800
Subject: [PATCH 5/5] Update llvm/lib/LTO/LTOBackend.cpp
Co-authored-by: Alexander Richardson <mail at alexrichardson.me>
---
llvm/lib/LTO/LTOBackend.cpp | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp
index 08955387ecfc3..3f074da042fc7 100644
--- a/llvm/lib/LTO/LTOBackend.cpp
+++ b/llvm/lib/LTO/LTOBackend.cpp
@@ -224,10 +224,7 @@ createTargetMachine(const Config &Conf, const Target *TheTarget, Module &M) {
TargetOptions TargetOpts = Conf.Options;
if (TargetOpts.MCOptions.ABIName.empty()) {
- StringRef ModABI = M.getTargetABIFromMD();
- if (!ModABI.empty()) {
- TargetOpts.MCOptions.ABIName = ModABI;
- }
+ TargetOpts.MCOptions.ABIName = M.getTargetABIFromMD();
}
std::unique_ptr<TargetMachine> TM(TheTarget->createTargetMachine(
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